One Gulf fisherman thought he was in for a giant catch, reeling in a four foot shark on his line off Florida's Bonita Springs north of Naples this week.

But no sooner than he had the black tip shark in his sights, a dark shadow appeared swimming up from the depths. A hungry grouper had other ideas about who was going to be sitting back with a full stomach Tuesday.

The video posted online (see below story) shows the grouper swallow the shark whole in one giant gulp and disappear back to the depths.

The mega fish is thought to be a Goliath grouper, a giant fish that can grow up to nine feet long and weigh 800 pounds, according to National Geographic magazine.